Does anyone have an example of this off the top of their heads? I need it for pedagogical purposes, not for a particular synthetic problem. I thought I had seen an example, possibly in March's book, but I am coming up empty right now, and I do not recall the details.
I found one example on-line (which comes from Clayden's textbook) in which a catalytic amount of lithium iodide sped up the production of a phosphonium salt from benzyl bromide and PPh3 in refluxing xylene. This will probably suffice for my purposes, but other examples that anyone has on hand would also be welcome.